I've seen the reason come up a few times during my research into it.
I believe this could be underdiagnosed though as I've found that when people ARE tested for D-Lactic Acidosis, they had to struggle with their Doctor before hand to get the test.
I believe this could be underdiagnosed though as I've found that when people ARE tested for D-Lactic Acidosis, they had to struggle with their Doctor before hand to get the test.